/*=====================================================================*
 *                   Copyright (C) 2011 Paul Mineiro                   *
 * All rights reserved.                                                *
 *                                                                     *
 * Redistribution and use in source and binary forms, with             *
 * or without modification, are permitted provided that the            *
 * following conditions are met:                                       *
 *                                                                     *
 *     * Redistributions of source code must retain the                *
 *     above copyright notice, this list of conditions and             *
 *     the following disclaimer.                                       *
 *                                                                     *
 *     * Redistributions in binary form must reproduce the             *
 *     above copyright notice, this list of conditions and             *
 *     the following disclaimer in the documentation and/or            *
 *     other materials provided with the distribution.                 *
 *                                                                     *
 *     * Neither the name of Paul Mineiro nor the names                *
 *     of other contributors may be used to endorse or promote         *
 *     products derived from this software without specific            *
 *     prior written permission.                                       *
 *                                                                     *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND              *
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,         *
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES               *
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE             *
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER               *
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,                 *
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES            *
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE           *
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR                *
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF          *
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 * POSSIBILITY OF SUCH DAMAGE.                                         *
 *                                                                     *
 * Contact: Paul Mineiro <paul@mineiro.com>                            *
 *=====================================================================*/

#ifndef __QFUNC_HH__
#define __QFUNC_HH__

#include <vector>

#include "fastonebigheader.hh"
#include "rating.hh"

namespace playerpiano
{
  template<typename PRating,
           typename Distribution>
  float
  qfunc (const PRating&                 prating,
         float                          logbeta,
         float&                         dlogbeta,
         float&                         ddlogbeta,
         const std::vector<float>&      pz,
         const std::vector<Rating>&     ratings,
         const Distribution&            priorlogbeta,
         float                          hq)
    {
      float beta = fastexp (logbeta);
      float q = hq;

      dlogbeta = 0;
      ddlogbeta = 0;

      for (unsigned int i = 0; i < ratings.size (); ++i)
        {
          for (unsigned int j = 0; j < pz.size (); ++j)
            {
              float dlogbetatmp;
              float ddlogbetatmp;

              q += pz[j] * prating.logprating (ratings[i],
                                               j,
                                               beta,
                                               dlogbetatmp,
                                               ddlogbetatmp);

              dlogbeta += pz[j] * dlogbetatmp;
              ddlogbeta += pz[j] * ddlogbetatmp;
            }
        }

      q += priorlogbeta.logpdf (logbeta);
      dlogbeta += priorlogbeta.dlogpdf (logbeta);
      ddlogbeta += priorlogbeta.ddlogpdf (logbeta);

      return q;
    }
}

#endif // __QFUNC_HH__
